"As you know, the Florida Senate developed and passed a bill in 2013 that would have created a premium assistance plan as a way to expand coverage," Gaetz wrote to Florida's Democratic U.S. Sen. Bill Nelsonon Thursday. "Subsequent to that action, we appealed to Secretary Sebelius for greater flexibility as a solution to the concerns that prevented an agreement ... on this important issue. Her response reiterated the previously issued rigid regulations.

"Now we are reaching out to Sylvia Burwell, the nominee to replace Secretary Sebelius, to ask her to reconsider several specific policies that block expansion in Florida and other states."

Florida is punting $51 billion in federal money by not expanding the joint state-federal Medicaid program to more than 900,000 uninsured who won't be covered by the federal health-care law. Republican senators have argued they want more flexibility to take the federal dollars and fund private managed care plans with them -- while House Speaker Will Weatherford, R-Wesley Chapel, has opposed expansion because he argued the federal government couldn't be trusted to pay most of the cost.

While Gov. Rick Scottreversed course and asked state lawmakers to accept the money last year, the effort has been basically shut down in the spring lawmaking session due to adjourn May 2.

Last month, Nelson visited the state Capitol and told Democrats he had a "secret plan" to try and finance Medicaid expansion in Florida through local tax dollars. That plan involves using what are called intergovernmental transfers (IGTs) to finance the state's share of the cost. IGTs are methods where local governments and taxing districts like hospitals pool dollars, drawing down more federal money to help meet the state's share of Medicaid costs.

But Gaetz wrote in a letter to state senators Thursday that the idea "does not appear to address the problems" recently expressed by the federal Centers for Medicare and Medicaid Services (CMS) with a similar way that Florida finances its health-care system for the poor: a fund hospitals pay into to draw down more federal cash, then dip into to pay for treating poor patients. That's because states that utilize multiple methods for pooling money can inflate the federal share of the costs and wind up increasing health-care costs.

In his letter, Gaetz notes that the fact the federal government is expressing concerns about that arrangement suggests it would be foolhardy to expand Medicaid without more flexibility to utilize block grants or other "market-based" reforms to discourage over-use of medical services.

"The prime focus should be on the lack of flexibility in the management and implementation of Medicaid in general and an expanded Medicaid program in particular," Gaetz wrote to Nelson. "Federal micro-management is a greater obstacle to expansion than funding source."

He then asks Nelson to support block grants of "shared risk models," which "would provide a meaningful contribution to enabling Florida to expand this coverage."